Roof fairings are employed on a variety of land vehicles, particularly truck tractors, for purposes of reducing drag. While efficient at reducing drag, the height of roof fairings are often a concern during what is known as “piggy back” shipping of truck tractors from the factory.
As shown in FIG. 1, during piggy back shipping a towing truck tractor 5 may tow two truck tractors 5″ and 5′″, which are secured to respective fifth wheels 6′ and 6.″ While piggy backing may be efficient for truck delivery, as shown in FIG. 1, the stacking of the truck tractors 5″ and 5′″ may cause roof fairings 10″ and 10′″ to extend above a height limit L, such as, for example, a bridge height limit.
Numerous two-piece roof fairing arrangements have been devised to overcome this problem, U.S. Pat. No. 4,919,472 to Wiley, Jr, U.S. Pat. No. 5,174,026 to Wiley, Jr. et al. and U.S. Pat. No. 5,755,485 to Christie et al. show two piece roof fairing arrangements connected by hinges that allow the height of the roof fairing to be lowered during shipment and then extended after delivery. During shipping, these arrangements permit an upper fairing body section to fit within a lower fairing body section that is mounted to the cab roof, whereby the overall height of the roof fairing is decreased. Advantageously, after delivery, the hinges in these arrangements allow the upper fairing, body section to easily move into an extended operable position, whereby the height of the roof faring is extended.
While such designs allow the height of roof fairings to be decreased during piggy back shipping, the permanent coupling via the hinges make for difficult, time consuming, and awkward factory manufacturing and installation. For example, due to the awkward shape, flexibility of the fairing walls, and combined weight of the hingedly connected upper and lower body sections, at least two workers would be are required to handle and mount the roof fairings in a factor setting. By way of another example, the use of piano hinges increases the manufacturing cost and assembly time. By way of yet another example, the use of a living hinge requires that the two fairing pieces be molded simultaneously with in a relatively large common mold.
The present invention is directed to an improved vehicle roof fairing.